Solenoid controlled, pilot air actuated valve assemblies having poppet valve cartridges are known in the prior art. U.S. patent application Ser. No. 232,262 , filed 08-15-89 discloses such a valve assembly in a vehicular central tire inflation system (CTIS), which system is also disclosed in U.S. Pat. No. 4,640,331. Both of these documents are incorporated herein by reference.
In the above mentioned application there is disclosed two normally open and one normally closed solenoid controlled, pilot air actuated valve assemblies for controlling inflation and deflation of vehicle tires from a central location. When each of these valve assemblies employs a poppet valve cartridge, they differ only with respect to whether the cartridge is normally open or closed, and only with respect to passages which direct fluid to and from a bore containing the cartridge in a body of the valve assembly.
An object of the present invention is to provide a modular cartridge which is readily assembled of identical components to be either normally open or closed, and which may direct fluid via standard passages in the valve assembly body, whereby normally open or closed valve assemblies are provided by a single design and inventory of cartridge components and valve assembly bodies.